SIDD isn't required to have a LUT

six/modules/c++/six.sicd/unittests/test_valid_sixsicd.cpp

@@ -149,5 +149,5 @@ TEST_CASE(test_read_sicd130_xml)
 TEST_MAIN(
     TEST_CHECK(test_createFakeComplexData);
     TEST_CHECK(test_read_sicd110_xml);
-    TEST_CHECK(test_read_sicd110_xml);
+    TEST_CHECK(test_read_sicd130_xml);
     )

six/modules/c++/six.sidd/unittests/test_valid_sixsidd.cpp

@@ -50,6 +50,11 @@ static std::filesystem::path schema_relative_path()
     return six_sidd_relative_path() / "conf" / "schema"; // .../conf/schema
 }
 
+static std::filesystem::path get_sample_nitf_path(const std::filesystem::path& filename)
+{
+    static const auto modulePath = six_sidd_relative_path() / "tests" / "sample_nitf";
+    return sys::test::findGITModuleFile("six", modulePath, filename);
+}
 static std::filesystem::path get_sample_xml_path(const std::filesystem::path& filename)
 {
     static const auto modulePath = six_sidd_relative_path() / "tests" / "sample_xml";
@@ -116,6 +121,19 @@ TEST_CASE(test_createFakeDerivedData_validate)
     test_createFakeDerivedData_(testName, true /*validate*/, six::sidd::Version::v300, six::sidd300::ISMVersion::v201609);
 }
 
+TEST_CASE(test_read_sidd200_no_LUT)
+{
+    static const auto pathname = get_sample_nitf_path("2023-07-26-11-37-27_UMBRA-04_SIDD.nitf");
+
+    six::XMLControlRegistry& xml_registry = six::XMLControlFactory::getInstance();
+    xml_registry.addCreator(six::DataType::DERIVED,
+        new six::XMLControlCreatorT<six::sidd::DerivedXMLControl>());
+
+    six::NITFReadControl reader;
+    reader.setXMLControlRegistry(xml_registry);
+    reader.load(pathname.string());
+}
+
 static void test_assert_unmodeled_(const std::string& testName, const six::UnmodeledS& Unmodeled)
 {
     TEST_ASSERT_EQ(1.23, Unmodeled.Xrow);
@@ -180,6 +198,7 @@ TEST_CASE(test_read_sidd300_v13_xml)
 TEST_MAIN(
     TEST_CHECK(test_createFakeDerivedData);
     TEST_CHECK(test_createFakeDerivedData_validate);
+    TEST_CHECK(test_read_sidd200_no_LUT);
     TEST_CHECK(test_read_sidd200_xml);
     TEST_CHECK(test_read_sidd300_xml);
     TEST_CHECK(test_read_sidd300_v13_xml);

six/modules/c++/six/include/six/NITFReadControl.h

@@ -278,6 +278,8 @@ struct NITFReadControl : public ReadControl
         return (iCat == "DED");
     }
 
+    void setDisplayLUT(six::NITFImageInfo&, const nitf::ImageSubheader&); // LUT processing for SIDDs
+
     // We need this for one of the load overloadings
     // to prevent data from being deleted prematurely
     // The issue occurs from the explicit destructor of

six/modules/c++/six/include/six/ReadControl.h

@@ -210,6 +210,10 @@ struct ReadControl
         if (!mXMLRegistry)
             mXMLRegistry = &XMLControlFactory::getInstance();
     }
+    void setXMLControlRegistry(const XMLControlRegistry& xmlRegistry)
+    {
+        setXMLControlRegistry(&xmlRegistry);
+    }
 
 protected:
     std::shared_ptr<Container> mContainer;

six/modules/c++/six/source/NITFReadControl.cpp

@@ -455,16 +455,41 @@ void NITFReadControl::load_(std::shared_ptr<nitf::IOInterface> ioInterface, cons
             }
         }
 
-        // SIDD 2.0 needs to read LUT directly from NITF
-        const auto pData = currentInfo->getData();
-        if (pData->getDataType() == DataType::DERIVED && pData->getVersion() == "2.0.0")
+        setDisplayLUT(*currentInfo, subheader);
+
+        currentInfo->addSegment(si);
+    }
+}
+void NITFReadControl::setDisplayLUT(six::NITFImageInfo& currentInfo, const nitf::ImageSubheader& subheader)
+{
+    // SIDD 2.0 needs to read LUT directly from NITF
+    const auto pData = currentInfo.getData();
+    if (pData->getDataType() != DataType::DERIVED)
+    {
+        // LUT processing only for SIDDs
+        return;
+    }
+
+    const auto version = pData->getVersion();
+    if (version == "1.0.0") // TODO: remove this hard-coded SIDD version check
+    {
+        // LUTs only with SIDD 2.0 and later
+        return;
+    }
+
+    // There's no requirement for SIDD 2.0 to have a LUT
+    const auto bandInfo0 = subheader.getBandInfo(0);
+    const int numLUTs = bandInfo0.getNumLUTs();
+    if (numLUTs > 0) // avoid getLookupTable() creating an empty nitf::LookupTable
+    {
+        const auto nitfLut = bandInfo0.getLookupTable();
+        if (nitfLut.getEntries() > 0)
         {
-            const auto nitfLut = subheader.getBandInfo(0).getLookupTable();
-            currentInfo->getData_()->setDisplayLUT(std::make_unique<AmplitudeTable>(nitfLut));
+            currentInfo.getData_()->setDisplayLUT(std::make_unique<AmplitudeTable>(nitfLut));
         }
-        currentInfo->addSegment(si);
     }
 }
+
 void NITFReadControl::load(std::shared_ptr<nitf::IOInterface> ioInterface, const std::vector<std::string>* pSchemaPaths_)
 {
     const std::vector<std::string> schemaPaths;